JP3883070B2 - Promotion pipe digging method - Google Patents

Description

  The present invention relates to a method for digging a propulsion pipe applied at the time of constructing an underground structure such as a sewer or telecommunications equipment, and more particularly to a propulsion pipe digging method capable of effectively reducing the propulsion resistance of the propulsion pipe.

  For the construction of underground structures such as sewers and telecommunications equipment, many pipe propulsion methods that do not require excavation of the ground surface are employed. FIG. 5 is an underground sectional view showing the procedure of the propulsion method. As shown in the figure, in the propulsion method, a start-up pile 1 is excavated on the start end side of the buried section, and a propulsion jack 2 for pushing out a propelling pipe is provided at the bottom of the start-up pile 1.

  In order to embed a propulsion pipe from the starting standing pile 1 into the ground, first, the propulsion machine 3 is operated from the bottom of the starting standing pile 1 to perform excavation toward the terminal end side of the burying section. And the earth and sand which generate | occur | produce in the underground of the propulsion machine 3 are removed from the excavation hole 4, and the propulsion pipe 5 is added to the excavation hole 4 by the propulsion jack 2 and inserted. In this way, the propulsion pipe 5 is embedded along the excavation hole 4 so that the propulsion pipe 5 is embedded in the embedded section.

  By the way, in the above-mentioned propulsion method, the outer diameter of the propulsion pipe 5 is set slightly smaller than the outer diameter of the propulsion machine 3, and the tail void material that serves as a lubricant between the diameter of the excavation hole 4 and the outer diameter of the propulsion pipe 5 is used. It is an indispensable element for accurately propelling a long distance and a curve to fill the tail void 6 and to secure the tail void 6. That is, when the filling rate of the tail void 6 around the propulsion pipe 5 is lowered, the frictional force of the propulsion pipe 5 with respect to the excavation hole 4 is increased, which may cause a problem in the propulsion of the propulsion pipe 5.

For this reason, conventionally, when the value of the main thrust of the propulsion jack 2 exceeds a preset abnormal thrust level, the lubricant is injected into the entire propulsion section to suppress the increase of the main thrust. An example of this is described in Patent Document 1.
JP 07-189591 A

However, if the lubricant is injected all over the propulsion section, it is possible to suppress the increase of the thrust force. However, the total length of the propulsion pipe 5 reaches several hundred meters at the end of the construction, so a large amount of lubricant is injected. There was a problem that construction cost would increase.
An object of the present invention is to provide a propulsion pipe excavation method capable of reducing the frictional force around the propulsion pipe at low cost by paying attention to the above-mentioned conventional problems.

  According to the present invention, if a thrust force is gradually applied to the end portion of the propulsion pipe fed into the ground, the interval between the joint portions is gradually reduced from the propulsion pipe on the propulsion jack side. This is based on the knowledge that the friction increasing range in the middle of the propulsion pipe can be specified by grasping the change in the thrust force with respect to the propulsion length based on the change in the relative position of the adjacent propulsion pipes.

  The value of the original pushing thrust of the propulsion jack 2 is used only for comparison with a preset abnormal thrust level, and the range of increase of the frictional force cannot be specified. However, in the propulsion tube area with normal frictional resistance, the thrust force increases so as to be approximately proportional to the propulsion tube length. It rises rapidly. For this reason, it is possible to specify the friction increase range in the middle of the propulsion pipe from the change in the thrust force.

By obtaining such a principle, the present invention specifies a friction increasing range in the middle of the propelling pipe when propelling the propelling pipe, and supplies a lubricant to the outer periphery of the propelling pipe located in the friction increasing range. The propulsion excavation is performed while reducing the overall propulsion frictional resistance. In this case, the friction increase range may be specified by capturing the change in the thrust force with respect to the propulsion length based on the change in the relative position of the adjacent propulsion pipes by applying the thrust force.

  This detects the main thrust of the propulsion pipe pushed into the ground by the propulsion method, and when the main thrust exceeds a preset abnormal thrust level, the pushing operation is temporarily stopped and the main thrust is initially set. Using the signal from the expansion / contraction detection sensor provided on the joint as a trigger, the value of the original pushing thrust with respect to the distance from the propulsion jack to the expansion / contraction detection sensor is sequentially measured by the measuring means to identify the friction increase range. Can be realized.

According to the above configuration, when the propulsion jack is operated and the thrust force is gradually applied to the end of the propulsion pipe, the thrust is sequentially transmitted from the propulsion pipe on the propulsion jack side. If the value of the main thrust when the relative position of the adjacent propulsion pipe changes is sequentially compared with the distance from the propulsion jack of the expansion / contraction detection sensor, the main thrust against the distance from the propulsion jack By detecting that increases, the range of friction increase in the propulsion pipe can be specified.
If the lubricant is injected into the friction increase range specified by the above procedure, the friction can be reliably reduced and the amount of lubricant injected can be minimized.

In this way, the friction increase range in the middle of the propulsion pipe when propelling the propulsion pipe is added by the main thrust. The propulsion pipe is configured by identifying and identifying the present invention so as to cause the excavation to be performed while supplying the lubricant to the outer periphery of the propulsion pipe located in this friction increasing range and reducing the overall propulsion friction resistance. The propulsion friction can be reliably reduced and the amount of lubricant injected can be minimized, thereby reducing the construction cost.

Specific embodiments of the propulsion pipe excavation method according to the present invention will be described below in detail with reference to the drawings.
FIG. 1 is a configuration explanatory view showing the configuration of a propulsion pipe peripheral frictional force measuring device used for realizing the propulsion pipe excavation method according to the embodiment. As shown in the drawing, a measuring device 10 (hereinafter, measuring device 10) for frictional force around a propelling pipe is applied to a propulsion method that does not require excavation of the ground surface.

  The propulsion method is performed by adding and inserting a propulsion pipe 12 such as a fume pipe or a steel pipe into an excavation hole provided by the propulsion machine, and a propulsion jack is used to push the propulsion pipe 12 into the excavation hole.

  Here, the structure of the propulsion pipe 12 is shown in FIG. As shown in FIG. 1 (1), a plurality of tail void injection holes 14 are provided in the circumferential direction on the side surface of the propulsion tube 12 inserted into the excavation holes one after another (three locations in the figure). The tail void material can be fed outward. Further, as shown in FIG. 2B, a joint 16 is provided between the propelling pipes 12 to be added. The joint 16 uses a packing type multi-curve thrust transmission device (MST (P-type)) so that the propulsion pipe 12 can be curvedly propelled, and can transmit the main thrust from the propulsion jack in a curved line. I have to. A steel collar 18 is provided around the outside of the joint 16 so as to prevent earth and sand from entering the pipe during propulsion.

  In this way, the joint 16 that is pushed into the ground together with the propulsion pipe 12 is provided with an expansion / contraction detection sensor 20 that constitutes the measuring device 10 so that a change in the relative position of the adjacent propulsion pipes 12 can be detected. Here, the expansion / contraction detection sensor 20 does not need to be provided for each continuous joint 16, and an arbitrary interval (for example, the sensor 20 is installed for each one of the joints 16) may be set according to the nature of the soil to be propelled. That's fine.

  A specific structure of the expansion / contraction detection sensor 20 is shown. The expansion / contraction detection sensor 20 includes a linear scale encoder 22, a pulse signal converter 26, and a counter input module 28. The plurality of expansion / contraction detection sensors 20 having such a configuration are connected to each other by a cable 30 and to a measuring means 32 provided outside the pipe. The change in the relative position of the adjacent propulsion pipes 12 is detected by the linear scale encoder 22, and the counter value is output from the counter input module to the measuring means 32.

  The expansion / contraction detection sensor 20 is connected to the measuring means 32, and an operation console 34 for performing the original pushing operation of the propulsion jack is also connected via a cable. The measuring means 32 stores in advance the distance from the propulsion jack in each of the expansion / contraction detection sensors 20, and uses the fluctuation value from the expansion / contraction detection sensor 20 as a trigger signal to measure the original pushing thrust of the propulsion jack from the console 34. A value is taken in, and the value of the original pushing thrust with respect to the distance from the propulsion jack of the expansion / contraction detection sensor 20 can be measured. Here, the determination of the plurality of expansion / contraction detection sensors 20 is performed by the line controller 24 installed inside the propulsion pipe 12, and the determination signal of the expansion / contraction detection sensor 20 is sent from the line controller 24 to the measuring means 32 together with the trigger signal.

  The measuring means 32 does not stick to dedicated equipment if the above conditions are satisfied, and in this embodiment, the personal computer 36 is used. An analog input module 38 and a linker 40 are provided immediately in front of the personal computer 36 so that signals from the expansion / contraction detection sensor 20 and the console 34 are taken into the personal computer 36. In the personal computer 36, the value of the original pushing force with respect to the distance from the propulsion jack of the expansion / contraction detection sensor 20 can be displayed on the screen, so that the situation can be grasped intuitively.

  Further, the expansion / contraction detection sensor 20 does not have to be particularly concerned with the above-described configuration, and a dial gauge type displacement measuring device is used instead of the linear scale encoder 22, or a digital signal is transmitted to the measuring means 32 instead of an analog signal. It may be used as

A procedure for applying the measuring apparatus 10 configured as described above to a propulsion method for underground excavation will be described.
FIG. 3 is a thrust state diagram showing the thrust fluctuation before the lubricant is introduced, and FIG. 3 (1) shows the fluctuation of the main thrust with respect to the propulsion length. The required thrust of the propulsion pipe 12 is determined by the resultant force of the face front resistance and the propulsion pipe peripheral resistance in the propulsion machine. Since the front resistance of the face of the propulsion machine in the ground is a constant value, and the resistance around the pipe is proportional to the sum (total length) of the length of the propulsion pipe 12 embedded in the ground, the ideal thrust line is a linear expression. Can be expressed as

  However, the value of the original pushing thrust with respect to the actual propulsion length does not draw a directly proportional line as shown in the above ideal thrust line because both the face front resistance and the propulsion pipe peripheral resistance fluctuate. Here, the increase portion of the main pushing thrust indicated by point C in the figure is investigated using the measuring device 10 to find the cause of the main pushing thrust increase. Note that the increase in the thrust force at point A and point B in the figure was due to the increase in the front resistance of the face of the propulsion machine. It can be judged from the fact that the increased friction range was not confirmed. That is, as described above, since the necessary thrust of the propulsion pipe 12 is determined by the resultant force of the face front resistance and the propulsion pipe peripheral resistance in the propulsion machine, if the friction increase range is not confirmed in the propulsion pipe peripheral resistance, It can be specified that the cause of the increase is an increase in the front resistance of the face of the propulsion machine. The reduction of the front face resistance can be achieved by cleaning the sludge valve and the cutter chamber of the propulsion machine.

  As shown in the state of point C, when the main thrust increases suddenly with respect to the ideal thrust line, the propulsion jack 12 is stopped once and the propulsion of the propulsion pipe 12 is stopped. After the propulsion work is temporarily stopped in this way, the measuring device 10 is operated and the propulsion jack is pressed against the end of the propulsion pipe 12 to gradually apply a force. Then, with the increase of the thrust force of the propulsion jack, the propulsion pipes 12 connected in multiple stages move one after another from the propulsion jack side in the propulsion direction of the propulsion jack, and the joint 16 portion contracts and the adjacent propulsion pipe 12 The relative position varies.

  Here, since the expansion / contraction detection sensor 20 is provided at the joint 16 portion of the propulsion pipe 12, trigger signals are sequentially generated from the expansion / contraction detection sensor 20 on the propulsion jack side. Then, using this trigger signal as a signal, the measurement means 32 measures the relationship of the original pushing thrust with respect to the distance from the propulsion jack to the expansion / contraction detection sensor 20. FIG. 2B is a graph showing the relationship of the original pushing thrust with respect to the distance from the propulsion jack to the expansion / contraction detection sensor 20. As shown in FIG. 2 (2), it can be confirmed that the value of the main pushing thrust increases rapidly in the range D in the figure. Further, since the front face resistance of the propulsion machine is reduced at the previous point A and point B, and the cause of the front face resistance of the face can be eliminated, the increase of the thrust force is caused by the range of D in the propulsion pipe 12 in the figure. It can be determined that the tightening is the cause. Since the increase in the thrust force is caused by a decrease in the filling rate of the tail voids accumulated around the outer periphery of the propulsion tube 12, the propulsion tube passes from the tail void injection hole 14 of the propulsion tube 12 belonging to D in the figure. The lubricant is fed to the outside of the outer wall 12 to reduce the friction around the outer side of the target propelling pipe 12.

  FIG. 4 is a thrust state diagram showing thrust fluctuation after the lubricant is introduced. As shown in the figure, it can be confirmed that the value of the original pushing thrust decreases after the lubricant is introduced at the point C. Thus, the range of tightening of the propulsion pipe 12 can be specified by obtaining the value of the main pushing thrust corresponding to each propulsion length. For this reason, it is not necessary to put a lubricant into the whole area of the propulsion pipe 12, and the consumption of the lubricant can be minimized.

  The present invention is applied at the time of constructing a pipe line of an underground buried object of a sewer or telecommunications equipment.

It is composition explanatory drawing which showed the structure of the measuring apparatus of the propulsion pipe periphery frictional force of the propulsion pipe excavation method which concerns on embodiment. FIG. 4 is an explanatory view showing the structure of a propulsion pipe 12. It is a thrust state figure which shows the thrust fluctuation | variation before lubricating material injection | throwing-in. It is a thrust state figure which shows the thrust fluctuation | variation after injection of a lubricating material. It is an underground sectional view showing the procedure of the propulsion method.

Explanation of symbols

  1 ……… Starting pile, 2 ……… Propulsion jack, 3 ……… Propulsion machine, 4 ……… Drilling hole, 5 ……… Propulsion pipe, 6 ……… Tail void, 10 ……… Propulsion pipe friction Force measuring device, 12 ......... Propulsion tube, 14 ......... Tail void injection hole, 16 ......... Fitting, 18 ......... Collar, 20 ...... Extension detection sensor, 22 ...... Linear scale encoder, 24 ... ...... Line controller, 26 ......... Pulse signal converter, 28 ......... Counter input module, 30 ......... Cable, 32 ......... Measuring means, 34 ......... Console, 36 ...... Personal computer, 38 ……… Analog input module, 40 ……… Linker.

Claims (1)

The range of friction increase in the middle of a propelling pipe when propelling the propelling pipe is identified by capturing the change in the pushing thrust relative to the propulsion length based on the change in the relative position of the adjacent propelling pipes , propulsion tube excavation method, wherein the propelling drilling while achieving a reduction in overall propulsion frictional resistance by supplying lubricant to the outer periphery of the propulsion tube located in this friction-increasing range.

Images